Controlling the amount of outside air entering a building is required to maintain pressurization, meet energy efficiency goals, confirm compliance with local building codes and maintain the health of the building and its’ occupants. The accurate measurement of outside airflow is required for the proper operation of today’s high performance buildings. Outside air can pose a challenge regarding the metering technology to choose due to low airflow velocities, high moisture content in certain climates and the presence of airborne contaminants at the point of measure.